The ultimate DIY speaker for AKSAs...

mb · « **on:** 11 Jan 2004, 02:37 am »

Thought this might catch you attention!

The Singapore folks had a small DIY fair, and Silicon Valley (the solid state room) had a treat:

A Linkwitz Orion set up with 3 AKSA Nirvanas. The Orion, Orion XO+EQ, GK-1 with remote relay volume control and two AKSAs were beautifully put together by Enrico. Fremen and mb provided AKSA 55Ns for the treble (took turns). Source was my modded CI-Audio dac, and my battery powered buffered attenuator alternated with the GK-1. Transport for Orions courtesy of EchiDna.

No time was available for positioning and tuning, but who needs it? The Orion is a great speaker. I've spent time with the VMPS RM40s, Piega C10s, top of the line MBL and others recently, and it's up there. My own Gradient Revolutions share identical woofer design (2xPeerless 12" in open baffle) as the Orions, and this design offers a quality of bass I've only previously heard on larger Apogee panels, driven by very large Krells. Perhaps the areas which could be improved is sound at lower/medium levels. The Orion liked to be played loud / very loud. I suspect the active XO was taking away just a little of the ultimate potential of the speaker.

The woodwork required is well beyond my abilities, so I don't see myself building a pair. For those of you who have the resources, you will rarely find a match for 3 AKSAs (only bass driver needs a 100N. 55Ns will blow you off on mid and treble).

Al Garay · « **Reply #1 on:** 13 Jan 2004, 06:00 am »

Thanks for sharing. Just to make sure I understood you correctly:

* 1 AKSA 100W 2-channel amp drove the 4 Peerless XLS (2 XLS per side in parallel)
* 1 AKSA 55W 2-channel drove the Seas W22 mids
* 1 AKSA 55W 2-channel drove the Seas Millenium tweeters

Is this correct?

Al

mb · « **Reply #2 on:** 13 Jan 2004, 06:31 am »

Yes, you got it. Via active LR4 crossovers, with EQ for the open baffle compensation. As you can imagine, the sound was quite effortless...

EchiDna · « **Reply #3 on:** 13 Jan 2004, 08:45 am »

I can only agree with MB, the sound was something to behold from those Orions... probably the best sound I've heard from a 2 speaker setup from top end to bottom end, outside of specially prepared listening rooms or people's private listening areas. When one especially considers the lack of effort spent on positioning and room setup, they were exceptional!

Effortless is a good descriptor and the open baffle concept won a few new admirers on the day...

The tweeters had a little something that wasn't quite there (In comparison to a set of DIY Accuton's) but the overall package was of very good bang for buck. Defintely worth a listen if you can ever swing a visit to an owner's place.

Al Garay · « **Reply #4 on:** 14 Jan 2004, 05:14 am »

I have read many excellent reviews about the SL Orion speakers both here and in the http://www.madisound.com/cgi-bin/discuss.cgi?. You know it is successful when there are several interesting dipole efforts such as:
* ThomasW/JonMarsh's Arvo project
http://www.htguide.com/CFBoards/index.cfm?fuseaction=Threads.viewthread&Tid=90041&Forum=6&StartRow=1&CFB=1
* JohnK's Nao project
http://www.geocities.com/kreskovs/NaO.html

The Orion, Arvo or Nao are in my upgrade path and will fit in my room better than my other dream speakers: SoundLab A-1 or M-1,
http://www.soundlab-speakers.com/a1.htm

I'm not sure AKSA 100watt Nirvana will do driving electrostats like the SoundLabs. I see a short upgrade path to go from my current system to the Nao system. I will need at least one more AKSA amp.

Al

andyr · « **Reply #5 on:** 14 Jan 2004, 08:07 am »

Quote from: Al Garay

I have read many excellent reviews about the SL Orion speakers both here and in the http://www.madisound.com/cgi-bin/discuss.cgi?. ...

Al,

The Phoenix is SL's later (and higher-specced) design. I reckon the "ultimate" system would have to be these, matched with a pair of his Thor subwoofers!

Regards,

Andy

Tinker · « **Reply #6 on:** 15 Jan 2004, 02:02 am »

Quote from: andyr

Quote from: Al Garay
I have read many excellent reviews about the SL Orion speakers both here and in the http://www.madisound.com/cgi-bin/discuss.cgi?. ...
Al,

The Phoenix is SL's later (and higher-specced) design. I reckon the "ultimate" system would have to be these, matched with a pair of his Thor subwoofers!

Hi Andy,
I am pretty sure Phoenix is an earlier design, which appeared about 5 years ago. The Orion represents a smaller version with a higher SAF/WAF rating. There is a great deal of design evolution to make the thing a lot more compact and use only one mid driver (Phoenix has two). The Phoenix is physically larger and has more oomph, and possibly slightly lower bass. IMHO if you did build a phoenix you probably wouldn't need a Thor. The Thor is an actively corrected monopole. The Phoenix sub is a dipole unit, mine has appreciable power down to 25Hz with a 3dB point at 16Hz (SL specs it at 13Hz). I suppose it depends how loud "loud" is. Give me a few days to get round to it and I'll make and SPL measurement with the preamp cranked.

T

Al Garay · « **Reply #7 on:** 15 Jan 2004, 06:06 am »

You are right. The Phoenix was first. The Orion is SL's second dipole and considered a significant improvement even compared to his Bethoven speakers.

Steve in Australia came up with an excellent design named Bob incorporating features from the Phoenix and Orion and using dual Adire 12" drivers which provide plenty of low-end extension. His site is very informative.
http://www.doddsy.net/steve6_009.htm

Enjoy,

Al

dayneger · « **Reply #8 on:** 18 Jan 2004, 03:54 pm »

These dipole speakers sound pretty interesting!

I've decided that any further steps I take in speakerhood should allow easy 2-channel/multichannel/HT integration. Have you seen any other examples of a 5 or more channel dipole rig?

One thing that makes me cautious about the dipoles, though, is the required amplification. On the assumption of 3 way L-R and 2-way center and rears you end up with a total of 12 channels of amplification!!

And that's just 5-channel.

Dayne

Al Garay · « **Reply #9 on:** 19 Jan 2004, 03:44 am »

You don't need to have a multi-channel dipole system. The idea is that with the balance and soundstage that you achieve with the SL Orion, you will be happy with a 2.1 system.

Otherwise, you can build speakers with matching drivers that are passive. For example, check out SteveD's site on the Bob and look at his center channel. It's like the top of the Orion without the bass module. There are many 2-way passive speakers that use the same compliment of drivers. Seas has a 2-way kit called the Trym that would work with the Orion.
http://www.seas.no/trym.htm

Enjoy,

Al

EchiDna · « **Reply #10 on:** 19 Jan 2004, 05:01 am »

the multi channel Orion (or Bob) user sure would need quite a few channels of amplification!

hmm lets see, 6 for the mains and then 2 for the centre and 4 for the rears... technically there would be little purpose in a sub with this type of system so you 'save' there, but still 12 channels of AKSA is going to make one heck of a statement in your loungeroom! not to mention the required crossovers and preamplification

geez... I better talk to the boss if I'm ever going to go down that road...
I better start saving!

dayneger · « **Reply #11 on:** 9 Feb 2004, 03:30 pm »

Just curious--wouldn't those Peerless XLS wired in parallel be a 2-ohm load? Or were they wired in series?

If I recall correctly, AKSA 100W units like mine are only happy down to about 3.6 ohms or so.

I just heard the Orions last week--very impressive! I think they'd sound even better with a better preamp than the Orion owner had--like a GK-1!

Dayne

dayneger · « **Reply #12 on:** 12 Feb 2004, 02:51 pm »

OK, a more accurate value--I just read somewhere else that the two Peerless 10" XLS wired in parallel drop to about 2.5 Ohms.

Hugh, wouldn't that make an AKSA 100W unhappy?

mb · « **Reply #13 on:** 12 Feb 2004, 03:44 pm »

You're right about that. I understand that the ultimate recommendation for Orion bass amplification is one amp per Peerless! Now that's a real luxury.

AKSA · « **Reply #14 on:** 12 Feb 2004, 08:33 pm »

The Peerless at 2.5R would certainly rock the boat; since power is required here I'd suggest two, one per driver. That would be a walk in the park....

Cheers,

Hugh

dayneger · « **Reply #15 on:** 8 Mar 2004, 05:55 pm »

Hi Hugh,

In this post you say that 2.5 ohms would rock the boat, and here you say that the 100W's happy down to 2.5 ohms, in reference to the same application. I have to admit that I'm a trifle confused!

Dayne

AKSA · « **Reply #16 on:** 8 Mar 2004, 11:33 pm »

Dayne,

2.5 ohms is on the limit I have chosen for these devices. It would work fine, but for a bass amp alone I'd be happier if it were closer to three ohms. Remember, the XLS is a very high output speaker driver, with prodigious bass SPL.

At these very low impedances amps work very hard, supplying a lot of current with a large net voltage drop across the device. This often threatens to enter the unsafe zone of operation and destroy the device.

My comments are not inconsistent; merely cryptic. Consider; we have 49 volt rails, and a 2.5R load. Let's put 8 amps into the load, four amps supplied from each of the two output devices in parallel, alternately from both rails. This puts, in non-reactive terms, 20V across the load. With 49 volts on the rail, say a couple of volts of sag due to heavy current draw, (47-20) volts across the output devices. With 27 volts across the device and 4 amps flowing through it, we are sailing close to maximum SOAR allowance, which at this voltage, consulting the curves, is 6A. If rail voltage should be a couple of volts higher, you can knock half an amp off this rating. Secondary breakdown is caused by exceeding SOAR ratings, if only for a few milliseconds, and is the Archilles heel of bipolars, which otherwise are fine devices. A safety margin of around 50% on SOAR is something I like to gun for where output stages do not have protection; it's excellent insurance.

So, the basic answer is this: 2.5R is a safe minimum with these woofers. But really crank up the volume and it might still be possible with an unthrottled, unprotected output stage to exceed SOAR ratings and blow up the output stage.

Unfortunately I'm the first to admit I'm fallible and make mistakes all the time. Mostly I get it right, but now and again I do confuse people! I apologize if this threw you.....

Cheers,

Hugh